1. Field of the Invention
The present invention relates to a planographic printing plate precursor, a method of producing the same, and a printing method using the same.
2. Description of the Related Art
Currently, in preparation of a planographic printing plate, image exposure has been performed using a computer-to-plate (CTP) technology. That is, a planographic printing plate precursor is directly scanned and exposed using a laser or a laser diode without using a lith film. Along with this, objects of a planographic printing plate precursor have been changed to improvement of image-forming characteristics, printing characteristics, and physical properties corresponding to the CTP technology.
From the growing interest in the global environment, environmental problems related to a waste liquid associated with wet treatments such as a development treatment have been closed up as a problem of a planographic printing plate precursor. Along with this, it is desired to simplify a development treatment or not to perform a development treatment. As one of a simple development treatment, a method referred to as “on-press development” has been suggested. In other words, the on-press development is a method of exposing a planographic printing plate precursor, mounting the planographic printing plate precursor on a printing press without performing a development treatment of the related art, and then removing an unnecessary portion of an image recording layer, at an initial stage of a typical printing step.
In a case where printing is performed using a planographic printing plate, since the end portions of the printing plate are in positions other than paper at the time of printing on paper having a size smaller than the size of the printing plate such as a typical sheet-fed press, the end portions do not affect the print quality. However, in a case where printing is continuously performed on roll-like paper using a rotary press during newspaper printing or the like, since the end portions of the printing plate are on the surface of rolled paper, the ink adhering to the end portions is transferred to the paper and forms linear stain (edge stain) and thus the commodity value of the printed matter is significantly impaired.
As a method of preventing edge stain on an on-press development type planographic printing plate precursor, a method of performing a treatment on a region within 1 cm from the end portions of the on-press development type planographic printing plate precursor for printing newspaper with a solution containing an organic solvent and a hydrophilic resin or a treatment solution containing an anionic or non-ionic surfactant has been suggested (see JP2011-177983A and JP2014-104631A).